Acute Salt Handling in Orthostatic Intolerance

Vanderbilt University

Status: Active, not recruiting

Conditions: Orthostatic Tachycardia; Orthostatic Intolerance; Postural Tachycardia Syndrome

Treatments: Other: normal saline (0.9%)

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00581633

K23RR020783 (U.S. NIH Grant/Contract)

061230

UL1RR024975 (U.S. NIH Grant/Contract)

P01HL056693 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

The investigators will test the hypothesis that patients with chronic orthostatic intolerance or postural orthostatic tachycardia syndrome (OI or POTS) will be unable to conserve urinary sodium as compared to healthy control subjects.

Full description

Patients with chronic OI appear to be hypovolemic with abnormalities in hormones that regulate salt & water handling. Increases in dietary salt have salutary effects on orthostatic tolerance in a physiological laboratory. The infusion of intravenous saline acutely decreased heart rate in this patient population. Preliminary data from Vanderbilt suggests abnormal salt handling in patients with chronic OI in a few patients. These data need to be confirmed and a better understanding of sodium handling in response to acute salt loads is required in these patients.

Enrollment: 30 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Diagnosed with orthostatic intolerance by Vanderbilt Autonomic Dysfunction Center (or healthy control subject)

Exclusion criteria

• Overt or acute cause for orthostatic tachycardia
• Hypertension (BP>145/95 or need for anti-hypertensive medications)
• QRS duration > 120 msec on EKG
• Pregnancy

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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30 participants in 1 patient group

1

Experimental group

Description:

saline infusion for sodium loading

Treatment:

Other: normal saline (0.9%)